Chewing gum ingredients are generally mixed according to mixing schedules to form a gum matrix, and the matrix is then sheeted, scored, and tempered before being formed into a gum product. Different chewing gums may require different mixing schedules. For example, sugarless gums, which contain glycerine and alditols, such as sorbitol and mannitol, are typically mixed according to the following schedule. After the chewing gum base is softened, usually by heating and mixing, a major portion of an alditol, usually sorbitol, is added as a bulking agent to form a matrix. Then glycerin is added to the softened matrix, and is dispersed by the sorbitol. Thereafter, another alditol, usually mannitol is added. The mannitol tends to dry the gum mixture, making handling and packaging easier.
When xylitol is one of the alditols added early in the mixing schedule, an unacceptable gum matrix is obtained. The matrix is soft and adheres to blades, rollers, and finishing knives, which makes it difficult to remove the matrix from the mixer, and difficult to sheet and score. The matrix also has a low dimensional stability, which further complicates sheeting, scoring and makes packaging difficult and expensive. A gum matrix with a low dimensional stability will not acceptably maintain its original thickness and width. Thus, a high dimensional stability gum matrix is preferred.